This invention relates to thermal fuses or temperature responsive circuit breakers which are simple in construction and yet high in precision of temperature sensitivity, and to a method of manufacturing such thermal fuses.
Generally, thermal fuses are roughly divided into two types, namely, one which uses an organic substance as its temperature sensing part and another which uses an inorganic substance as its temperature sensing part.
The type which uses an organic substance is capable of (instantaneous disconnection) but is poor in weather resistance and moisture-resistance. Therefore, it must be hermetically sealed. But when it is used at a place or under a condition where ambient temperature fluctuations are large, the hermetical sealing is lost due to thermal expansion or thermal shrinking of a receptacle, material used, etc. and erroneous motion is often caused. On the other hand, the type which uses an inorganic substance is inferior to the former type with respect to the fusible characteristic but is not necessarily required to be hermetically sealed. Therefore, the latter type has been used widely.
The thermal fuse according to the present invention makes the most of the merits of both types and is designed to be good for continuous use under conditions of high temperature.